public class ClassInitTest {
    private static int num = 1;
    static {
        num = 2;
        number = 20;
        System.out.println(num);
//        System.out.println(number);// 非法的前向应用
    }

    private static int number = 10;  // linking之prepare: number=0 --> initial: number=20 --> number=10
    public static void main(String[] args) {
        System.out.println(ClassInitTest.num);
        System.out.println(ClassInitTest.number);  // 10
    }
}
